As U.S. credibility and stature diminish in world affairs, the American president and his secretaries of state and defense engage in eloquent denial. Unfortunately for them, realities trump words, even persuasive ones.

At the World Economic Forum in Davos, "where the water-cooler chatter was about America's waning influence in the Middle East," John Kerry proclaimed himself "perplexed by claims... that somehow America is disengaging from the world." Nothing could be further from the truth, he asserted: "We are entering an era of American diplomatic engagement that is as broad and as deep as any at any time in our history." Likewise, Defense Secretary Chuck Hagel has called for "a renewed and enhanced era of partnership with our friends and allies."

In this spirit, Obama has made multiple promises to reassure allies.

To South Korea, which depends on the American "tripwire" to deter a demented dictator who could flatten Seoul within the first few hours of an artillery barrage, Obama promised that "The commitment of the United States to the Republic of Korea will never waver."

To Japan, which depends on the U.S. Seventh Fleet to deter increasingly aggressive Chinese encroachment on the Senkaku Islands, he reaffirmed that "The United States remains steadfast in its defense commitments to Japan," which the State Department specifically indicated includes the Senkaku Islands.

To Taiwan, whose security against the Peoples Republic depends on the American deterrent, he "reaffirmed our commitment to… the Taiwan Relations Act," which requires the United States to maintain the capacity "to resist any resort to force or other forms of coercion that would jeopardize the security of" Taiwan.

To the Philippines, worried about its territories in the South China Sea claimed by China, particularly the Spratly Islands and Scarborough Reef, he reaffirmed a commitment to the 1951 Mutual Defense Treaty that provides, in the event of an armed attack, that the United States "would act to meet the common dangers."

To Saudi Arabia, alarmed by Obama's appeasement of Iran in the Joint Plan of Action, he reiterated "the firm commitment of the United States to our friends and allies in the Gulf."

And to Israel, isolated in a sea of enemies, Obama declared "America's unwavering commitment to Israel's security," because standing by Israel "is in our fundamental national security interest."

•Record numbers of Americans believe that U.S. global power and prestige are declining, according to the Pew Research Center. For the first time in surveys dating back to the 1970s, "a majority (53 percent) says the United States plays a less important and powerful role as a world leader than it did a decade ago," while only 17 percent thought American power has been enhanced. An even larger majority, 70 percent, "say the United States is less respected than in the past." And 51 percent say Obama is "not tough enough" in foreign policy and national security issues.

•More than two thirds have a negative opinion of Obama's handling of Iran, the Mellman Group found; a majority (54-37 percent) support targeted military strikes against Iran's nuclear facilities rather than allowing Iran to develop nuclear weapons.

•McLaughlin & Associates finds that 49 percent of respondents think that America's standing has been diminished during Obama's five years in office; 40 percent think America's adversaries now look at Obama with contempt.

Second, Pew Research reports that half the publics in Britain, France, and Germany, as well as a third in the U.S. and Russia, see China eventually replacing the United States as the world's leading superpower. Two-thirds of Israelis think Obama will not stop the Iranians from getting nuclear weapons.

Third, world leaders in countries as varied as Japan, Poland, and Israel hear Obama's promises as unrelated to reality. Speaking for many, Josef Joffe of Germany's Die Zeit weekly finds "consistency and coherence to Obama's attempt to retract from the troubles of the world, to get the U.S. out of harm's way. … to be harsh about it, he wants to turn the U.S. into a very large medium power."

Successful "diplomatic engagement" (as Kerry calls it) must be backed by consistency, power, and will, not by nice words, hollow promises, and wishful thinking. Will the Obama administration realize this before doing permanent damage? Watch the Iranian nuclear deal for possible changes, or not.